 Smallest, most common, single-celled organisms that lack a nucleus

 Archaebacteria  Eubacteria

EUBACTERIA ARCHAEBACTERIA  live everywhere  Some cause disease  Cell wall: peptidoglycan  Example: Escherichia coli  Cell wall: not peptidoglycan  Typically do not cause disease  Example: methanogens (produce methane gas)

SHAPES FORMATIONS  Bacilli  Rod-shaped  Cocci  Spherical-shaped  Spirilla  Spiral-shaped  Strepto = chains  Staphylo = grape-like clusters

 Get energy by consuming organic molecules made by other organisms

CHEMOHETEROTROPHSPHOTOHETEROTROPHS  Take in organic molecules for energy and a supply of carbon  Example: humans  Photosynthetic (use light for energy) but need to take in organic compounds as carbon source

 Make own food from inorganic molecules

 Use light energy to convert carbon dioxide and water to carbon compounds and oxygen  Example: cyanobacteria

 Make organic carbon from carbon dioxide and get energy from chemical reactions involving ammonia, hydrogen sulfide, nitrites, sulfur, or iron  Example: bacteria in deep ocean

BINARY FISSION CONJUGATION  When reaches max. size, replicates DNA and goes through mitosis  No exchange of DNA material  A hollow bridge forms between two bacteria that allows genes to travel from one cell to another

 When conditions are unfavorable, spores form and lie dormant for months until conditions are favorable again.  Some are resistant to heat, dryness, and lack of nutrients.

 Decomposers – helps environment recycle nutrients into soil for use by other organisms  Nitrogen fixers – convert nitrogen gas into a form plants can use  Human uses: food production and digestion (symbiotic relationship), oil spill clean-up

 Damage cells and tissues of infected organisms directly by breaking down the cells for food  Example: Mycobacterium tuberculosis  Release toxins (poisons) that travel throughout the body interfering with the normal activity of host  Example: Streptococcus

 Compounds that block the growth and production of bacteria  Can be used to cure many diseases and prevent infections

 Sterilization by heat – exposure to high heat for extended period of time  Example: pasteurization  Disinfectants – chemical solutions that kill pathogenic bacteria  Food storage and processing  Refrigeration, cooking, preservatives

 Particle of nucleic acid, protein and in some cases, lipids.  Enter living cells and use the machinery of the infected cell to produce more viruses.

 DNA or RNA core  Protein coat called capsid  Includes proteins that bind to receptors on a cell’s membrane and trick it into allowing it to enter

 Viruses that infect bacteria

 A virus enters a cell, copies itself, and causes the cell to burst.  Host cell is lysed and destroyed.  Steps:  Bacteriophage injects DNA into cell  Cell copies viral DNA and parts  Parts assembled into new viruses and cell bursts open

 Host cell makes copies of virus indefinitely.  Viral genetic information (prophage) integrates its DNA into DNA of host  Viral genetic info replicates with host’s for several generations  Prophage can exit host cell at any time and enter lytic cycle.

 Viruses that contain RNA as genetic info  Get name b/c genetic info is copied backwards; from RNA into DNA  Example: HIV

 DNA or RNA core & capsid, no cell membrane  Reproduce only in host cell  No growth or development  Do not obtain or use energy  Do not respond to environment

 A preparation of weakened or killed pathogens  Sometimes causes the body to produce immunity to the disease

 Viruses produce diseases by disrupting the body’s normal equilibrium  Some kill cells (poliovirus)  Some change growth and development of cells (warts)